No need to show anything except your passport and destination ticket. You will meet with only Airline staff and no immigration officer.

I work in the airport and that's not true.You have to pass TSA security (homeland security).You will show your passport,papers and sign a paper

if you have plans to return to US I suggest that you first talk with an immigration attorney, if you have overstayed you visa you might have breached visa status and could be penalized and not be able to return from 1 to 5 or even 10 years.

@Nina MR i have my passport with me ,what other document to show please? and what is that paper for ,which needs to be signed. will there be a permanent ban for re-entering in US?

@Long Waiting thanks for the info. i don't intend to Re- enter US.. in this case what will be the penalty

There are many details to be considered, that is reason you need to talk with an specialist immigration attorney. An US Bar status may affect visas to other locations later on. You can read more from USCIS website: https://www.uscis.gov/laws-and-policy/other-resources/unlawful-presence-and-inadmissibility I’m sharing general information, it may or may not applies to your case.

If you intend to not return, there will be no penalty at all. Because you will only meet airline staff who will scan your passport and not any immigration officer. No need to be scared bro. But your reentry is going to be complicated for sure..